Before they even took the field on Saturday night at Progressive Field, the Guardians had witnessed enough playoff push pressure for one day. They watched on a clubhouse television as the rival White Sox fended off late threats from the Tigers in one of those anxious September games in which every pitch comes with a complimentary panic attack and a side of ulcers. The heart can only take so much of that. So with their American League Central lead temporarily trimmed to a half-game by Chicago’s win, the Guards, who know they have to beat the Sox in the division outright because of the tiebreaker, went out and walloped the A’s. Not much tension here. Just a five-run first, a five-run third, a two-homer night from Angel Martínez and a 12-6 victory lap for a Cleveland club (80-75) that remains a game up on the South Siders (79-76) in the race for the AL Central title and the first-round bye that quite possibly comes with it. “It’s just fun baseball, right?” said Chase DeLauter, whose three-run blast in the first inning erased a 2-0 deficit on a night in which the Guards never looked back. “This is what you play all year for.”